Die for coating fiber-insulated wire



R. H.l DENHAM DIE FOR COATING FIBER-INSULATED 'WIRE Filed June 2, 1944 inve-anton Rbert H. Denham` x Hi AttornegA ,July 31, 1945.

Patented July 3 1, 1.945

2,380,728 DIE FOB COA-TING FIBER-INSULATED WIRE Robert HfDenham, Scotia, N. Y., assignor to General Electric Company, `a corporation of New York Application June 2, 1944, Serial No. 538,521

3 Claims.

The present invention relatesz to dies for coating liber-insulated wires, that is, wires that have been insulated with iibrous material such as cotton, silk, or glass iibers. A varnish treatment of such wires by means of enamel, varnish, lacquer,

or like viscous coating material, especially a treatment with the hydrolysis product' of polyvinyl acetate increases considerably the mechanical strength and the electric resistance of the insulation. In case of wires provided with an insulating material of glass fibers, the varnish treatment or coating is absolutelyv essential before use of the wire in order to permit handling without damaging the very brittle glass bers.

The object of my invention is to provide an improved construction and arrangement of dies for coa-'ting ber-insulated wires;

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 illustrates an apparatus for coating fiber-insulated wires including a die embodying my invention; Fig. 2 is an enlarged sectional view of av part of Fig. 1 showing my .improved die; and Fig. 3 is a perspective view of the die'shown in Fig. 2;

The coating apparatus (Fig. 1) comprises a container I for viscous coating material 2. A

material from the wire after it leaves the container and forces the remaining coating material into the crevices and interstices Aformed by and between the fiber insulating material there- The die Bvincludes two blocks of elastic material such as rubber, felt, or certain plastics. The blocks are located above and in contact with each other and are forced towards opposite sides of the wire. During operation the wire gradually cuts grooves or slots into the blocks. The walls of the grooves completely surround and engage the surface of the wire along its entire circumference. More specifically, asshown in Figs. 2

fiber-insulated, round or rectangular Wire 3 to Y be coated is drawn from a pay-off reel 4 over a guide sheave 5 immersed in the body of liquid coating material 2. The vwire upon leaving the container is covered with an excessive amount of v liquid coating material. In order to remove such excessive amount of coating material and to form a substantially uniform coating on the wire, it is pased through a die'S. secured to the lower end of a baking oven 1. The latter has spaced'paralle] walls 8,' 9 and in the present example is heated by a plurality of electric heating elements I0 .coating inthe oven. Finally, after the baking of the last coating the wire is woundonto a take- -up reel I3. The die 6 removes excess coating disposed within recesses in the walls 8, 9. The s, lower end of the wall 8 has a channel I| for adand 3, the die comprises a bracket I4 which has a horizontal wall portion I5 and two vertical portions I6 and I1. The portion I6 is secured to the lower end of the oven wall 8. The portioxr- I1 acts as a support for a supporting member in the form of an angle iron I8, which latter has a vertical leg I9 secured to the portion `|1 byA screws 20 and a horizontal leg 2|. A block or plate of rubber or like elastic material 22 is rigidly secured to the vertical leg I9 of the angle iron I8 by means of two brackets or lugs 23 and 24, gripping opposite edge portions of the block 22 and fastened to the angle iron by the aforementioned screws 20. A second block 250i rubber or like elastic material is disposed vertically above the first block 22. The second block 25 is held in acasing 26 which has two side walls 21, a bottom 28 and two end walls 29. The lowerv edges'of the walls 21 and 29 are formed with a plurality of lingers or lugs bent around the block 25 firmly to hold the latter within the casing. The bottom 28 and the left-hand end wall 29 have a plurality of parallel slots 3|. The casing for the second block is slidably held between guides 32, 33 secured to the horizontal leg 2| of the angle iron I8 by screws 34. The casinar is biased towards the left in Fig. 2 by means of a tension spring 35 secured at its right-hand vend to pins 36 extending from the bottom 28 casing. The' wire 3 to be coated is then placed in front of the rst block 22. In thepresent example where the wire is provided with three successive coatings three parallel portions of the wire are placed in front of the block 22. 'There-- upon the second block 25 with its casing is slipped l into the entrance of the guides 33 and connected to the arm 31 by the biasing spring 35.

During operation the wire gradually lengthens the slots 40 in the second block and at the same time cuts similar slots 4| into the rst block. 'I'he slots 4| are not as deep as the slots 40 because the wire 3 engages the rst block along its width and the second block along its length. After a certain period of operation the slots 40 reach the end of the slots 3| and at about the same time the slots 4I extend through the width of the block 22. 'I'he blocks then are replaced by new blocks. The front of the rst block 22 engages the wire 3 from one side and the grooves in the block 25 engage the wire from the opposite side. The grooves cut into the two cooperating blocks having rounded ends which during operation engage the wire surface along the entire circumference thereof. The spring 35 forces the second block 25 towards the right-hand side of `the wire and thereby forces the opposite side of the wire into the grooves of the rst block. Excessive varnish on the wire is thereby removed and the remaining varnish is forced into crevices formed between the ilbrous material on the wire and is uniformly distributed over the surface of the wire insulation. The resilient quality of the blocks and the biasing action between the blocks and the wire assures uniformity of the coating action and precludes damage to the iibrous insulating material. The die illustrated in the drawing constitutes a multiple coating die because it operates at the same time on separate parts of a single wire or on several separate wires.

Thus with my invention 1 have accomplished an improved die for coating fiber-insulated wire. This die broadly includes two blocks or plates of rubber or like resilient material. One of the plates is vertically mounted while the other plate is mounted horizontally directly above or below the first mentioned plate. The second plate is slidable and biased with one of its edges in the direction of the front surface of the first mentioned plate.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that .the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. bie for lcoating ber-insulated wire comprising a horizontally extending angle iron having a vertical and a horizontal leg, a block of resilient material rigidly mounted on the vertical leg, guide means secured to the horizontal leg, a casing and a second block of resilient material therein slidingly mounted in the guide, and means l biasing the casing across the horizontal leg.,

2. Die f or coating fiber-insulated wire compising a supporting member, a. wiping plate, clamps securing the wiping plate to the suppcrting member, guide means secured to and partly formed by the supporting member, a casing with another wiping plate therein having a bottom with a plurality of parallel slots extending through the edges 'thereof being slidingly held in the guide means, and a biasing spring for forcing the casing along the guide means. 5

3. Die for coating liber-,insulated wire compris- 4ing a plate of wiping material, means including clamps for vertically mounting the plate, another plate of wiping material, means horizontally mounting the other plate directly above the first mentioned plate, and means biasing an edge portion of the otherl plate in the direction of the front surface of the-. rst mentioned plate.

1 ROBERT H. DENHAM. 

